Two-phase projectile

ABSTRACT

A device for transferring energy to propel a payload with added velocity after launch includes a first component having a mass (m 1 ), and a second component having a mass (m 2 ). As an assembly, the first and second components are positioned to establish a compression chamber between them that is dimensionally responsive to their relative movements. And, a payload is mounted on a selected component of the assembly. In operation, a driving force is exerted against one component of the assembly to propel the entire assembly along a predetermined flight path. Contemporaneously with this acceleration, the two components are moved toward each other. In turn, this compresses gas in the gas chamber to generate potential energy that is transferred as the gas expands to separate the payload from the assembly with added velocity.

FIELD OF THE INVENTION

The present invention pertains generally to man-powered devices for launching projectiles. More particularly, the present invention pertains to projectiles which transfer pneumatic energy to a payload, in flight, to increase the payload velocity, after the projectile has been launched. The present invention is generally, but not exclusively, useful for projectiles that convert the kinetic energy from a launched projectile into potential energy of a compressed gas inside the projectile, and then transfer this potential energy as kinetic energy to a payload in the projectile, for increased payload velocity after the initial launch.

BACKGROUND OF THE INVENTION

An important factor for evaluating the performance of a man-powered launcher is the velocity at which a projectile is released from the launcher. Regardless whether the projectile is an arrow, a bolt, or a shot cluster, and regardless whether the projectile is launched by either a vertical bow or a crossbow, the resultant projectile velocity is an important measure of the launcher's performance. In the event, the resultant projectile velocity will be a function of the amount of energy (i.e. the capacity to perform work) that can be stored in the launcher prior to projectile launch, and thereafter used to propel the projectile onto its flight path. For the specific case of a man-powered weapon, a contributing factor for performance is the physical ability of the user.

In general, energy can be classified as being either thermal energy, potential energy or kinetic energy. Of primary interest here are potential and kinetic energy. By definition, potential energy is the energy which is possessed by a body by virtue of its position or condition relative to other bodies. For example, an object weighing one pound, when positioned ten feet above a surface prior to being dropped onto the surface, will expend ten foot-pounds of energy when it impacts against the surface. In this example, by virtue of its position relative to the surface, the one pound object had a potential energy of ten foot-pounds. As another example of potential energy, a compressed gas has a potential energy for performing work as it is allowed to expand. On the other hand, unlike potential energy, kinetic energy is the energy (work capacity) that a body possesses by virtue of being in motion. Mathematically expressed, kinetic energy is a function of the velocity of the object. Specifically, a particle having a mass “m”, that is moving with a linear velocity “v”, has a kinetic energy that is mathematically expressed as “½ mv²”. As is well known, potential energy and kinetic energy are interchangeable.

In light of the above, it is an object of the present invention to provide a device and method for converting the potential energy of a launching device into the potential energy of a compressed gas inside the projectile during a launch of the projectile; and then transferring this potential energy to a payload for use as kinetic energy that will increase velocity of the payload after the initial launch. Another object of the present invention is to provide a device and method for launching a projectile to achieve an in-flight velocity that otherwise exceeds the capability of the launching device. Still another object of the present invention is to provide a device and method for launching projectiles with a pneumatically assisted operational velocity that is easy to use, is simple to implement and is comparatively cost effective.

SUMMARY OF THE INVENTION

In accordance with the present invention, a device and method are provided for launching a projectile from a man-powered device which will achieve an in-flight velocity that otherwise exceeds the capability of the launching device by itself. More specifically, in an energy transfer sequence, the potential energy that is initially established in the projectile launcher is converted into kinetic energy for the projectile as the projectile is launched onto its flight path. Next, the kinetic energy that is imparted to the projectile is then, at least in part, converted into potential energy by compressing gas in a chamber, inside the projectile. In turn, this potential energy is transferred to a payload, as the compressed gas is allowed to expand, for use as kinetic energy that will increase payload velocity after the initial launch. Note that this multistep energy conversion process occurs in a dynamic fashion, such that various steps of the process may overlap in time.

Structurally, a device for the present invention includes a first component that is tubular shaped and is formed with a lumen which defines an axis. Further, the first component has an open end and a closed end. Also included in the device of the present invention is a second component that is engaged with the first component to create an assembly. Specifically, this assembly establishes a gas-filled compression chamber in the lumen of the first component that is located between the second component and the closed end of the first component. Within this combination, the assembly allows for a substantially free axial movement of the second component back and forth in the compression chamber of the assembly. Further, depending on the embodiment of the present invention, a payload is selectively mounted on a component of the assembly. For the present invention, the payload may be either a conventional arrow (e.g. a broadhead) as used with a vertical bow (launcher), a bolt as used with a crossbow (launcher), or a shot cluster that may be adapted for use by either type launcher.

As envisioned for the present invention, a man-powered launcher will be used to generate an axially-directed driving force on one component of the assembly (projectile) in order to propel the projectile from the launcher and onto its flight path. A consequence of this driving force is to cause a relative movement between the first component and the second component. Recall, the second component is free to move within the lumen of the first component (i.e. it is free to move within the gas chamber of the assembly). In the event, this movement further compresses gas in the compression chamber to thereby increase potential energy in the compressed gas. Once gas in the compression chamber has been compressed as much as possible, which occurs at or about the time when the driving force becomes zero, the gas then begins to expand. During this expansion, potential energy in the gas is converted to kinetic energy by equal and opposite forces to both the first and second components. This causes a resultant increase in the velocity of one component, and a resultant dissipation in the velocity of the other component; a combination of events that separates the payload from the assembly.

With the above in mind, the present invention envisions two different types of operational embodiments. In one, the payload is mounted on the second component, and the driving force is generated on the first component. In the other embodiment, the payload is mounted on the first component and the driving force is generated on the second component. In either embodiment, the mass of the proximal (i.e. aft) component (m_(p)) can be less than the mass of the distal (i.e. forward) component (m_(d)). For both embodiments, the driving force for launch is exerted against the proximal component.

For an operation of the present invention, a launcher is selected and is configured (i.e. armed) for launch. Stated differently, the launcher is configured to store potential energy. A projectile is then positioned on the launcher for launch. Upon firing the launcher, the potential energy that is stored in the launcher is converted to kinetic energy by way of the driving force that acts to propel the projectile from the launcher. Specifically, this driving force acts on the projectile and is directed to accelerate the projectile along an axial path that is defined by the projectile.

During the initial acceleration of the projectile by the driving force, a first kinetic energy is generated for the first component of the assembly, and a second kinetic energy is generated for the second component of the assembly. All of this happens for separate but interrelated reasons. Specifically, the different components of the assembly will preferably be of different mass, and they can have different velocities at launch (recall: kinetic energy equals ½ mv²). In more detail, the different velocities occur because, while the driving force acts directly on the first component to accelerate it along the flight path, the second component experiences no such direct force. Instead, the second component tends to remain at rest and is accelerated only by forces exerted on it by the gas which is compressed in the compression chamber.

Simultaneously, as kinetic energy is imparted to the first and second components of the assembly, a potential energy is stored within the gas in the gas-filled chamber of the assembly. Specifically, this increase in potential energy occurs because the second component moves toward the first component during the initial acceleration, and the gas is compressed between components as the gas chamber is diminished in size. At the end of the first component's initial acceleration, the gas has been compressed as much as possible and it has its highest potential energy.

After the initial acceleration of the projectile (i.e. when the driving force becomes zero), the potential energy of the gas is converted into kinetic energy and an expansion of the gas acts on both the first component and the second component. The result here is an additional acceleration of the second component and its payload for separation of the payload from the projectile (assembly), and by a deceleration of the remainder of the projectile.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of this invention, as well as the invention itself, both as to its structure and its operation, will be best understood from the accompanying drawings, taken in conjunction with the accompanying description, in which similar reference characters refer to similar parts, and in which:

FIG. 1A is an elevation view of a projectile in accordance with the present invention, shown mounted on a vertical cross bow for launch;

FIG. 1B is a view of the projectile as shown in FIG. 1A with the projectile at the release point where it is launched from the launcher;

FIG. 1C is a view of the projectile as shown in FIGS. 1A and 1B with the payload in flight toward a target after the payload has separated from the remainder of the projectile;

FIG. 2 is a side view of a first preferred embodiment of a projectile in accordance with the present invention;

FIG. 3 is a side view of an alternate second preferred embodiment of a projectile in accordance with the present invention;

FIG. 4A is a cross section view of a first preferred embodiment of the projectile of the present invention as seen along the line 4-4 in FIG. 2, prior to a launch of the projectile;

FIG. 4B is a cross section view of the first preferred embodiment of the projectile as seen in FIG. 4A, at its release point, as it is being launched from the launcher;

FIG. 4C is a cross section view of the first preferred embodiment of the projectile as seen in FIGS. 4A and 4B, after a payload has been separated from the remainder of the projectile;

FIG. 5A is a cross section view of a second preferred embodiment of the projectile of the present invention as seen along the line 5-5 in FIG. 3, prior to a launch of the projectile;

FIG. 5B is a cross section view of the second preferred embodiment of the projectile as seen in FIG. 5A at its release point, as it is being launched from the launcher; and

FIG. 5C is a cross section view of the second preferred embodiment of the projectile as seen in FIGS. 5A and 5B after a payload has been separated from the remainder of the projectile.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring initially to FIG. 1A, a device in accordance with the present invention is shown and is generally designated 10. As shown, the device 10 includes a projectile 12 and a man-powered launcher 14. In the particular case of the device 10 that is shown in FIG. 1A, the launcher 14 is a vertical bow of a type well known in the art. The launcher 14, however, could as well be a crossbow (not shown) or an air gun (not shown), both of which are of types well known in the pertinent art.

As illustrated sequentially in FIGS. 1A, 1B and 10, a purpose of the present invention is to use the launcher 14 to propel the projectile 12 along a flight path (dashed line) 16 toward a target 18. In sequence, FIG. 1A shows the launcher 14 in a configuration for firing the projectile 12. FIG. 1B then shows the projectile 12 as it is being released from the launcher 14. And, FIG.

10 shows the projectile 12, and its payload 20 after it has been separated from the projectile 12 in flight, after launch. In particular, FIG. 10 shows that shortly after launch, the payload 20 continues along the flight path 16 toward the target 18, while the projectile 12, itself, falls to the ground along a separation path (dotted line) 22.

From an energy perspective, FIG. 1A shows a projectile 12 that is ready to be shot from a launcher (vertical bow) 14. In detail, the launcher 14 is configured to have a useable potential energy that can be converted into the kinetic energy of motion for the projectile 12. FIG. 1B on the other hand, shows the projectile 12 at its release point from the launcher 14, after the potential energy in the launcher (FIG. 1A) has been transferred to the projectile 12 as an internal mixture of potential energy and kinetic energy. In FIG. 10, the payload 20 is shown after its separation from the projectile 12.

In terms of energy transfer, the separation of payload 20 from projectile 12 is caused when a portion of the kinetic energy in the projectile 12 (at launch, FIG. 1B) is pneumatically converted into potential energy of compression inside the projectile 12, and then reconverted into kinetic energy for the payload 20. With this reconverted kinetic energy, the velocity “v” of the payload 20 is increased sufficiently to separate the payload 20 from the projectile 12. Importantly, the payload 20 will substantially maintain the increased velocity “v”.

FIGS. 2 and 3, respectively, show two different embodiments for the present invention. In detail, FIG. 2 (with cross reference to FIGS. 4A-C) shows a projectile 12 which includes a proximal component 24 that defines an axis 26. For this embodiment of the present invention, a distal component 28 is positioned inside the proximal component 24 (see FIG. 4A). In another embodiment of the present invention, which is shown in FIG. 3, the distal component 28′ is positioned on the outside of the proximal component 24′. Both embodiments, respectively, include a nock 30 (30′) that is attached to the proximal component 24 (24′). Further, the embodiment for the device 12′ that is shown in FIG. 3 also includes a plurality of fletches 32 that are attached to the distal component 28′, and a plurality of fletches 34 that are attached to the proximal component 24′.

With reference to FIG. 4A, it will be appreciated that the proximal component 24 is an elongated tube which is formed with a lumen 36 that extends along the length of the proximal component 24. The lumen 36 has an open end 37, and it has an arresting ring 38 which is located proximate the open end 37. At the other end of the proximal component 24, the nock 30 is affixed to the proximal component 24 to establish a closed end for the lumen 36. FIG. 4A also shows that the distal component 28 of the projectile 12 is a cartridge 40 which holds a payload 20. For the embodiment of the projectile 12 shown in FIGS. 4A-C, the payload 20 is a shot cluster. Further, the cartridge 40 is shown to include a stabilizing ring 42 and a sealing ring 44 that together maintain an axial alignment for the cartridge 40 as it moves back and forth along the axis 26 inside the lumen 36 of the proximal component 24.

Still referring to FIG. 4A, with the distal component 28 (i.e. cartridge 40) positioned inside the lumen 36 of the proximal component 24, it will be appreciated that a compression chamber 46 is established between the cartridge 40 and the nock 30 of the projectile 12. Importantly, the sealing ring 44 establishes a substantially air-tight seal for the compression chamber 46. On the other hand, as evidenced by cross reference with FIGS. 4B and 4C, the cartridge 40 must be allowed to freely move back and forth inside the lumen 36 of the proximal component 24. Stated differently, it is essential to the operation of the present invention that the compression chamber 46 be dimensionally variable.

FIGS. 5A-C show another embodiment of the present invention wherein a compression chamber 48 is established in the lumen 36′ of the distal component 28′ of the projectile 12′. Specifically, for this embodiment, a sealing ring 50 is provided on the proximal component 24′ that interacts inside the lumen 36′ with the distal component 28′. With this interaction, a compression chamber 48 is established between the components 24′ and 28′. As with the compression chamber 46 for the embodiment of the projectile 12 (see FIGS. 4A-C), it is essential to the operation of the projectile 12′ of the present invention that the proximal component 24′ move freely relative to the distal component 28′, and that the compression chamber 48 thereby also be dimensionally variable.

In an operation of the present invention, a driving force 52 (represented by the arrows 52 in FIGS. 4A and 5A) is applied to the projectile 12 (12′) by way of the nock 30 (30′). This occurs during a transformation of the launcher 14 between the consecutive configurations shown in FIG. 1A and FIG. 1B. As shown in FIGS. 4A-C, the effect of this driving force 52 on the projectile 12 is at least three-fold. For one (see FIGS. 1A and 1B), the projectile 12 will be accelerated to a launch velocity “v” for release from the launcher 14. Simultaneously, in a second effect (see FIGS. 4A and 4B), the relatively unrestrained distal component 28 (i.e. cartridge 40) is caused to move forward more slowly (i.e. toward nock 30), against the resistance of gas in the compression chamber 46. Thirdly, gas in the compression chamber 46 is compressed by the relative movement of the distal component 28 (cartridge 40) as the dimensions of the chamber 46 become smaller (see FIG. 4B).

After the projectile 12 has been launched from the launcher 14 (see FIG. 1B), the driving force 52 no longer acts to accelerate the projectile 12. Also, the potential energy that was generated by compressing gas in the compression chamber 46 reaches its maximum. As gas in the compression chamber 46 is then allowed to expand, its potential energy is converted into a kinetic energy that is manifested by an increased velocity for the cartridge 40, and its payload 20. This increased velocity then causes the payload 20 to separate from the cartridge 40 and to continue along the flight path 16 (see FIG. 1C). At the same time, as gas in the compression chamber 46 expands, the conversion of potential energy into kinetic energy is also manifested as a decrease in the velocity of the proximal component 24. As intended for the present invention, this decrease in velocity of the proximal component 24 will result in the proximal component 24 being launched at a substantially lower velocity than the payload. A special case involves component 24 falling (generally vertically) to the ground along the separation path 22 (see FIG. 10).

A similar operational scenario occurs for the embodiment of projectile 12′ as shown in FIGS. 5A-C. More specifically, as evidenced by a comparison of FIG. 5A with FIG. 5B, the driving force 52 acts on the nock 30′ to accelerate the projectile 12′. This also compresses gas in the compression chamber 48 in the distal component 28′. In this case, however, the payload 20′ is mounted directly on the distal component 28′ and, thus, both the payload 20′ and distal component 28′ are separated from the proximal component 24′. In the event, expanding gas in the compression chamber 48 acts to increase the velocity of the distal component 28′ (payload 20′) and to diminish the velocity of the proximal component 24′.

While the particular Two-Phase Projectile as herein shown and disclosed in detail is fully capable of obtaining the objects and providing the advantages herein before stated, it is to be understood that it is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as described in the appended claims. 

What is claimed is:
 1. A device which comprises: a first component, wherein the first component is tubular shaped, is formed with a lumen and defines an axis, and wherein the first component has an open end and a closed end; a second component engaged with the first component to create an assembly, wherein the assembly provides for a back and forth axial movement of the second component in the lumen of the first component, and establishes a gas-filled compression chamber in the lumen of the first component between the second component and the closed end of the first component; a payload mounted on a selected component of the assembly; and a launcher for generating an axially-directed driving force on the assembly to propel the assembly from the launcher and onto a flight path in the axial direction with an initial relative movement between the first component and the second component to compress gas in the compression chamber and generate potential energy in the compressed gas for use in separating the payload from the assembly in flight.
 2. A device as recited in claim 1 wherein, during an initial acceleration of the assembly by the driving force, a first kinetic energy is generated for the first component and a second kinetic energy is generated for the second component of the assembly, and a potential energy is generated for the gas in the gas-filled chamber of the assembly.
 3. A device as recited in claim 2 wherein, after the initial acceleration of the assembly, the potential energy of the gas is transferred into kinetic energy with an expansion of the gas to accelerate the payload for separation of the payload from the assembly and to decelerate any remainder of the separated assembly.
 4. A device as recited in claim 1 wherein the second component is a cartridge for holding the payload, and the driving force is generated on the first component, and further wherein the payload is separated from the second component, in flight, after launch.
 5. A device as recited in claim 1 wherein the payload is mounted on the first component and the driving force is applied to the second component.
 6. A device as recited in claim 1 wherein the launcher is man-powered.
 7. A device as recited in claim 6 wherein the launcher is a vertical bow.
 8. A device as recited in claim 6 wherein the launcher is a crossbow.
 9. A device as recited in claim 1 wherein a mass (m₁) of the first component is not equal to a mass (m₂) of the second component.
 10. A device which comprises: a first component having a mass (m₁); a second component having a mass (m₂), wherein the first component and the second component are positioned in an assembly for relative movement therebetween; a payload mounted on a selected component of the assembly; and an enclosed gas chamber established between the first and second components, wherein the gas chamber is dimensionally responsive to movements between the first and second components for compressing gas in the gas chamber to generate potential energy in the compressed gas for subsequent use as the gas expands to separate the payload from the assembly.
 11. A device as recited in claim 10 wherein the first component is tubular shaped, is formed with a lumen and defines an axis, and wherein the first component has an open end and a closed end, and further wherein the assembly establishes a gas-filled compression chamber in the lumen of the first component between the second component and the closed end of the first component, and provides for a back and forth axial movement of the second component in the compression chamber.
 12. A device as recited in claim 11 further comprising a launcher for generating an axially-directed driving force on the assembly to propel the assembly from the launcher and onto a flight path in the axial direction with an initial relative movement between the first component and the second component to compress gas in the compression chamber and generate potential energy in the compressed gas for use in separating the payload from the assembly in flight.
 13. A device as recited in claim 12 wherein the second component is a cartridge for holding the payload, and the driving force is generated on the first component, and further wherein the payload is separated from the second component.
 14. A device as recited in claim 12 wherein the payload is mounted on the first component and the driving force is generated on the second component.
 15. A device as recited in claim 12 wherein the launcher is man-powered.
 16. A device as recited in claim 12 wherein the launcher is a vertical bow.
 17. A device as recited in claim 12 wherein the launcher is a crossbow.
 18. A method for transferring energy to propel a payload, the method comprising the steps of: providing an assembly, wherein the assembly includes a first incompressible component having a mass (m₁) and a second incompressible component having a mass (m₂), and a compressible component aligned along an axis extending between the first and second incompressible components, wherein the compressible component is responsive to relative movements between the first and second incompressible components; mounting the payload on the second incompressible component of the assembly; exerting an axially directed driving force against a selected incompressible component to establish a kinetic energy for the assembly, and to cause the first and second incompressible components to move along the axis toward each other; generating a potential energy in the assembly as the compressible component is compressed between the first and second incompressible components in response to relative movements thereof; and converting the potential energy generated in the compressible component into kinetic energy with equal and opposite forces acting respectively against the first and second incompressible components to dissipate kinetic energy in one incompressible component, to increase kinetic energy in the other incompressible component and to cause separation of the payload from the assembly with increased velocity.
 19. A method as recited in claim 18 wherein the compressible component is a gas.
 20. A method as recited in claim 18 wherein the exerting step is accomplished using a man-powered launcher. 